The present invention relates to a sorption filter material, in particular an adsorption filter material, according to the preamble of claim 1, which is suitable, in particular, for producing protective materials of all types (for example protective suits, protective gloves, protective shoes and other items of protective clothing and also protective coverings, e.g. for ambulances, sleeping bags and the like) and also for producing filters and filter materials and is thus suitable for both the military sector and the civilian sector, in particular for NBC use.
The present invention further relates to the use of this sorption filter material, in particular adsorption filter material, in the abovementioned protective materials and in the above-described filters and filter materials and also the abovementioned protective materials and the abovementioned filters and filter materials themselves.
There are a number of substances which are absorbed by the skin and lead to severe bodily injury. The blister-producing mustard gas (Yellow Cross) and the nerve poison Sarin may be mentioned as examples. Human beings which may come into contact. with such poisons have to wear suitable protective clothing or be protected against these poisons by suitable protective materials.
Protective suits which are impermeable to air and water vapor, for example, which are equipped with a rubber layer which is impermeable to chemical poisons are known for this purpose. A disadvantage is that these suits very quickly lead to heat buildup since they are impermeable to air and water vapor.
However, protective suits against chemical weapons which are intended for prolonged. use under a variety of conditions must not lead to heat buildup for the wearer. For this purpose, protective suits which are permeable to air and water vapor and offer a high degree of comfort for the wearer are known.
The permeable protective suits which allow passage of air have an adsorption filter layer comprising activated carbon which very lastingly binds the chemical poisons so that even strongly contaminated suits pose no risk to the wearer. The great advantage of such systems is that the activated carbon is also accessible from the inside, so that poisons which have got in through damaged regions or other permeable places can be adsorbed very quickly.
The adsorption layer in the above-described permeable protective suits which allow passage of air can be configured so that, for example, either activated carbon particles, in particular activated carbon grains or spheres, having an average size of up to about 2.0 mm are bound to small spots of adhesive printed onto a textile support material or else a reticulated polyurethane foam impregnated with a carbon paste composed of binder and activated carbon is employed as adsorption layer, with the adsorption layer generally being supplemented by an outer material (i.e. a covering material) and is covered by a light textile material on the inside facing the wearer.
Furthermore, there are also composites which comprise a sheet-like activated carbon fiber structure, e.g. an activated carbon fiber nonwoven or woven activated carbon fabric (cf., for example, WO 94/01198 A1 or the preceding EP 0 649 332 B1 or EP 0 230 097 A2).
Owing to its quite unspecific adsorptive properties, activated carbon is the most widely used adsorbent. Activated carbon is generally Obtained by carbonization (also known synonymously as low-temperature carbonization, pyrolysis, burning, etc.) and subsequent activation of carbon-containing starting compounds, with preference being given to starting compounds which lead to economically sensible yields (cf., for example, H. v. Kienle and E. Bäder, “Aktivkohle und ihre industrielle Anwendung”, Enke Verlag Stuttgart, 1980).
However, the production of activated carbon is relatively energy-consuming. Furthermore, impregnation with metal salts has hitherto been necessary in order to achieve a desired adsorption efficiency, which represents an additional process step. Furthermore, the adsorption filter materials produced in this way do not always have the desired regenerability. In addition, the porosity and pore size distribution cannot readily be adjusted or tailored.